Internal combustion engine starter mechanism

ABSTRACT

Starter mechanism for a high speed engine having epicyclic output speed reduction gearing rendering cranking difficult. A starter pinion shaft with a pinion at an inner end and a starter pulley at an outer end, the shaft slidable inwards and outwards for engagement and disengagement of the pinion with a ring gear applying multiplied torque to the crankshaft through a part of the reduction gearing. Beveled teeth on nondriving faces of the teeth of the pinion provide automatic disengagement as the engine starts.

United States Patent Inventor Leopold W. Llewellyn Burnaby, British Columbia, Canada App]. No 843,127 Filed July 18, 1969 Patented Feb. 9, 1971 Assignee Kal-Pac Engineering Ltd.

Vancouver, British Columbia, Canada a corporation of British Columbia Priority July 23, 1968 Great Britain 35081/68 INTERNAL COMBUSTION ENGINE STARTER MECHANISM 4 Claims, 5 Drawing Figs.

US. Cl 123/185 Int. Cl F02n l/l00 FieldofSearch... 123/179K,

l85Cl, 185C, 185A, 1858, 1858-1, 1853-2, 55

[56] References Cited UNITED STATES PATENTS 2,895,466 7/1959 ,Mall et al 4 123/185 $329,134 7/1967 Llewellyn 123/55 FOREIGN PATENTS 8,365 6/1915 Great Britain 123/185 Primary ExaminerMark M. Newman Assistant Examiner-Ronald B. Cox Attorney-Lyle G. Trorey ABSTRACT: Starter mechanism for a high speed engine having epicyclic output speed reduction gearing rendering cranking difficult. A starter pinion shaft with a pinion at an inner end and a starter pulley at an outer end, the shaft slidable inwards and outwards for engagement and disengagement of the pinion with a ring gear applying multiplied torque to the crankshaft through a part of the reduction gearing. Beveled teeth on nondriving faces of the teeth of the pinion provide automatic disengagement as the engine starts.

SHEEIIUFZ Leopold w. Llewellyn,

n or

l e y T rorey, Agent PATENIEDFEB 91ml 356L415 sum 2 0F 2 Lopolcl w. Llewellyn,

Inventor by Lyle G. ro rey,

Agent INTERNAL COMBUSTION ENGINE STARTER MECHANISM BACKGROUND OF INVENTION of small size. This isa highspeed engine characterized by av relatively small number of moving parts and avoids the use of connecting rods, teaching an unusual crank shaft motion such that power takeoff is efi'ected by means of an epicyclic train providing a speed reduction ratio between the crankshaft and a power output shaft so that the latter is driven atreduced speed. y

The present invention relates to a cranking mechanism particularly but notexclusively' for usewith this engine in which,

if cranking is attempted through the epicyclic power takeoff mechanism cranking torque required is multiplied by the epicyclic train ratio.

SUMMARY or THE INVENTION The cranking torque can be reduced by using a pinion concentric witha hollow power output shaft, thus utilizing a gearing advantage and applying increased torque to the crankshaft. This structure permits use of a small light starter.

motor, or other starting means, and simplified starter gearing.

Inthepresent invention a'lstarter pinion, teeth of which are beveled on a nondrivin'g side, is provided and this pinion meshes with a driven ringgear for starting purposes. When the engine starts, the driven ring gear becomes a driving gear which initially tends to drive the starter pinion. Reaction at the bevel now acts to urge the starterpinion axially out of engagemerit, a helical compression Spring being provided to assist disengagement. a

- DESCRIPTION OF DRAWINGS FIG. I is a longitudinal section of starter. mechanism according to the invention, with some parts not shown in section.

FIG. 2 is afragmented detail of a starter pinion showing a bevelofatooth. i

FIG. 3 shows the starter pinion and a ring gear, as seen from 3-3 FIG. 1. 1

FIG. 4 is a view from 3-3 of FIG. 1 at enlarged scale, additionally a crankshaft web is shown in broken outline.

FIG. 5 shows the starter assembled to an internal combastion engine of the U.S. patent, the engine and starter being generally in section.

PREFERRE EMBODIMENT A detail description following, related to drawings, gives exemplification of preferred embodiment of the invention which, however, is capable of expression in structure other than that particularly described and illustrated. The description isof the starter as applied to an engine of U.S. Pat. No. 3,329,l34.

DESCRIPTION OF FIGS.

1 AND 2\VITH REFERENCE T was 1 As disclosed in the U.S. patent aforesaid, axes of power cylinders and charge cylinders intersect at right angles, the intersection being on a main crankcase axis or centerline of the engine shown in FIG. 5.

In FIG. I, a starter mechanism is designated generally 10. A hollow power output shaft 11 having a bore 12 and'an outer end 13 is concentric with the axis A, the shaft being joumaled in an integral sleeve bearing I4 mounted in a housing [5. Power is taken off the engine by a sprocket I6 secured to the shaft 11. An integral flywheel and cooling fan I7 is also secured to the shaft 11. A starter pinion shaft I8 is concentrically joumaled within the shaft 1 I, the pinion shaft having an integral starter pinion 19 at one end, and at an opposite end 20 a starter drive means, namely a pulley 21, is secured the pulley being adapted for rope starting; or for connecting to a starter motor, not shown-in which latter alternative V-belt drive is provided. Alternatively a pinion, not shown, can be substituted for the pulley with obvious chain or gear drive.

The bore 12 is counterbored at an inner end to accept the starter pinion 19, the counterbore terminating at a shoulder 22. An end of thebore I2 remote from the shoulder 22 has an outer counterbore 23 to accept a sleeve 24 of the starter pulley, the sleeve having an inner end 24.]. A coil compression spring 25, an inner end of which bears against a shoulder 26 formed by the counterbore 23, extends within the bore from the said shoulder to the sleeve inner end 24.1.

The starter pinion 19 has involute teeth 27, outer ends of the teeth being beveled as seen at 28 FIG. 2. An inner shoulder 29, as shown, is defined'by a change in diameter of the starter pinion shaft which is slidable. Relevant dimensions are such that, when'the pulley 21 is pushed inwards of the hollow shaft I], there is, asse en in FIG. I,'an axial separation of the shaft shoulder 29 from the counterbore shoulder 22. The spring is of such length that. in a normal or disengaged position, the starter pulley 21 is urged away from the sprocket 16, thus urging the shoulder 29 against the shoulder 22. In the I position shown in FIG. I, with axial spacing between the shouldersthe starter. pinion is in meshing engagement with a starter ring gear 30 having internal teethwhich engagement is best seen in FIG; 3. As is later explained, the ring gear 30 is secured to a gear of an epicyclic output train of the engine so that rotation of the ring gear turns the engine over.

The starter pinion involute tooth bevels 28 are formed on nondriving faces of theteeth, as shown in FIG. 2. The bevels are at an angle of about 45 to the axis'A, which angle is not critical within plus or minus about 5. The bevels tend to urge within the counterbore of the power shaft 11 where it is held in the disengaged position by the spring with the shoulders 22 and 29 in contact.

DESCRIPTION OF FIGS. 3 AND 4 AND FURTHER REFERENCE TO FIGS. I AND 5 A takeoff pinion 31 of the engine is shown in fragmented broken outline in FIG. I, and is shown fragmented in FIG. 3. The starter ring gear 30 is mounted concentric and integral with the pinion 31, and the pinion 3l meshes with a ring gear 32 secured to the power shaft 11; the ring gear 32 being a part of the epicyclic train of the engine, as is the pinion 31. As disclosed in the said U.S. patent, the ring gear 32 takes the power ofi' the crankshaft of the engine through the pinion 31, which is mounted on an extension of the crankshaft. The takeoff pinion 31 is a part of the epicyclic reduction train of the en gine. An axial centerline of the integral gears 31 and 30 is designated .I in FIGS. 3 and 4, and coincides with acenterline of the crankshaft designated D-which, as described in the U.S. patent, extends through a midpoint of a crankshaft web 33, as seen in FIG. 4, where the crankshaft extension is designated 34 and shown in broken outline. A crankpin 35 has a centerline designated H in FIG. 4, H and A being equidistant from D. The takeoff pinion of the engine is in mesh with the flywheel ring gear 32 on one side of the engine centerline A as seen in FIG. I, whilst the starter pinion 19, (which is coaxial with the centerline A), is, in starting, simultaneously in mesh with the starter ring gear 30 on a diametrically opposite side of the 'engine centerline.

Referring particularly to FIG. 4, the ring gear 30 is secured by bolt means 36 (shown only in FIG. 4) to the engine takeoff pinion 31 so that these two gears are integral as aforesaid.

DESCRIPTION OF FIG. 5

In FIG. 5 the starter is shown assembled to an internal combustion engine 40 according to the US. Pat. No. 3,329,134. The housing of the starter is bolted at 41 to a housing 42 of the engine 40 as shown. The epicyclic gear 31 is shown, the starter ring gear 30not visable in FIG. 5being secured thereto as explained, and the epicyclic ring gear 32 is shown in engagement with the gear 31. A part of the starter pinion is seen, the pulley 21 being shown engaged as in FIG. 1.

It is seen that the instant starter structure in combination with a part of the epicyclic reduction train of the US. patent effects torque multiplication.

OPERATION The starter pulley 21 FIG. 1 has a flange slot 37 for a knot of rope, not shown. In operation, the starter pulley 21 is pushed in until an inner boss 44 thereof bears against the outer end 13 of the power shaft 11. In this position, the spring 25 is compressed and the starter pinion 19 engages the starter ring gear 30. When the rope is pulled, friction between driving faces of the teeth is sufficient to hold the pinion in engagement against disengaging face of the spring. Pulling the rope applies torque to the shaft 18, the torque being tension of the rope acting through an arm which is the radius of the pulley 21. It is seen from the FIG. 4 that this torque is multiplied by the ratio of the pinion l9 and ring gear diameters. The multiplied torque is applied about the axes D and J, so turning over the engine to start it.

I claim:

1. Starter mechanism for an internal combustion engine having a crankshaft and speed reduction means driving a hollow power output shaft (11) at a speed less than that of the crankshaft; in combination with the speed reduction means a starter mechanism characterized by:

a. a starter pinion shaft l8) concentrically journaled in the hollow output shaft and slidable axially thereof, the starter shaft having a starter pinion (19) at one end and a starter drive means (21) at an opposite end; the pinion having teeth (27) with bevels (28) formed on nondriving faces thereof;

a starter ring gear (30) having internal teeth adapted for meshing engagement with.the teeth of the pinion, and

being mounted on and concentric with a takeoff pinion (31) of the speed reduction means to rotate therewith;

and

. a compression spring (25) urging the starter pinion shaft to slide axially of the hollow shaft in a direction to move the starter pinion out of engagement with the ring gear; constructed and arranged for the starter drive means to be slidable axially inwards against the spring for meshing engagement of the starter pinion and the starter ring gear so that rotation of the starter drive means rotates the crankshaft, with meshing engagement being maintained by force between driving faces of the teeth, and so that when the engine starts the ring gear momentarily drives the starter pinion, reactions of the ring gear teeth and the bevels of the starter pinion teeth then effecting disengagement.

2. Mechanism as defined in claim 1, the starter drive means having an inner boss (44) which, when the drive means is pressed inwards, bears against an outer end (13) of the power shaft when the starter pinion and ring gear are in-meshing engagement as aforesaid.

3. Mechanism as defined in claim 2, an inner shoulder (29) defined b a change in diameter of the starter pinion shaft, and a counter ore at an inner end of the hollow output shaft defining a shoulder (22), the shoulders limiting outward slidable movement of the starter pinion shaft (11) and defining a position of disengagement of the starter pinion and ring gear, the counterbore being adapted to accept the starter pinion.

4. Mechanism as defined in claim 3, the hollow power output shaft (11) having an outer counter (23) to accept a sleeve (24) of the starter drive means and defining a shoulder (26), with the spring (25) extending in compression between the two shoulders last aforesaid. 

1. Starter mechanism for an internal combustion engine having a crankshaft and speed reduction means driving a hollow power output shaft (11) at a speed less than that of the crankshaft; in combination with the speed reduction means a starter mechanism characterized by: a. a starter pinion shaft (18) concentrically journaled in the hollow output shaft and slidable axially thereof, the starter shaft having a starter pinion (19) at one end and a starter drive means (21) at an opposite end; the pinion having teeth (27) with bevels (28) formed on nondriving faces thereof; b. a starter ring gear (30) having internal teeth adapted for meshing engagement with the teeth of the pinion, and being mounted on and concentric with a takeoff pinion (31) of the speed reduction means to rotate therewith; and c. a compression spring (25) urging the starter pinion shaft to slide axially of the hollow shaft in a direction to move the starter pinion out of engagement with the ring gear; constructed and arranged for the starter drive means to be slidable axially inwards against the spring for meshing engagement of the starter pinion and the starter ring gear so that rotation of the starter drive means rotates the cRankshaft, with meshing engagement being maintained by force between driving faces of the teeth, and so that when the engine starts the ring gear momentarily drives the starter pinion, reactions of the ring gear teeth and the bevels of the starter pinion teeth then effecting disengagement.
 2. Mechanism as defined in claim 1, the starter drive means having an inner boss (44) which, when the drive means is pressed inwards, bears against an outer end (13) of the power shaft when the starter pinion and ring gear are in meshing engagement as aforesaid.
 3. Mechanism as defined in claim 2, an inner shoulder (29) defined by a change in diameter of the starter pinion shaft, and a counterbore at an inner end of the hollow output shaft defining a shoulder (22), the shoulders limiting outward slidable movement of the starter pinion shaft (11) and defining a position of disengagement of the starter pinion and ring gear, the counterbore being adapted to accept the starter pinion.
 4. Mechanism as defined in claim 3, the hollow power output shaft (11) having an outer counter (23) to accept a sleeve (24) of the starter drive means and defining a shoulder (26), with the spring (25) extending in compression between the two shoulders last aforesaid. 